At least one receiving antenna, whose features are well known, is used to carry out a measurement of a transmitting antenna or test antenna radiation diagram. This receiving antenna is separated from the transmitting antenna to be measured by a certain distance, for example a distance of less than a few meters. To do this, the transmitting antenna, which forms part of an electronic device, is placed with the other components of the electronic device on or in a support element. The support element is then placed on a positioning device, which may be of the random type, i.e. able to move or orient the support element in any direction for measuring the electromagnetic field generated by the transmitting antenna.
According to the state of the art, as described, in particular, by U.S. Pat. No. 6,191,744 and JP Patent No. 2003-043083, it is known to perform a transmitting antenna radiation diagram measurement using at least one receiving antenna, moved around the transmitting antenna. To do this, the electronic device that includes the transmitting antenna is placed on a fixed support, whereas the receiving antenna is mounted on a mechanical structure, such as arms, for moving the receiving antenna relative to the transmitting antenna. The receiving antenna can be moved around the transmitting antenna at a fixed distance from the transmitting antenna. Each position of the receiving antenna is detected by position detecting means linked to the mechanical structure. In this manner, signals relating to the electromagnetic field that are picked up by the receiving antenna and positions signals are supplied to a data processing station, for calculation of the transmitting antenna radiation diagram.
One drawback of this type of state of the art measuring system lies in the fact that the mechanical structure that carries the receiving antenna is relatively complicated. With this measuring arrangement, this means that data signals cannot be provided to the processing station with the accuracy required for calculating the transmitting antenna radiation diagram.
U.S. Pat. No. 3,441,936 describes a device for positioning a spherical element in which a transmitting antenna can be placed. This spherical element is held, by gravity, on three drive wheels of the positioning device that are capable of orienting the transmitting antenna in any direction. When one drive wheel is being driven, in order to move the spherical element, the spherical element skids onto the other two drive wheels. This means that proper positioning of the transmitting antenna cannot be guaranteed, which is a drawback.